1. Field of the Invention
The present invention relates to a developing device and an image forming apparatus that uses this developing device and a process cartridge.
2. Description of the Related Art
In recent years, in image forming apparatus such as copiers, printers, facsimile apparatus, and compound machines that combine at least two of these functions, it has been the standard that users change the developing device or process cartridge. Therefore, there is a requirement for a constitution in which the developing device or process cartridge can be easily inserted and removed. As a result providing the developing device or process cartridge with a grip has already been proposed, as disclosed in for example, Japanese Patent Application Laid-open No. H6-332304.
However, color is becoming more widespread in image forming apparatus as described above; in particular the tandem type having a plurality of image carriers is superior for speed, so it is becoming the mainstream. Among this type of apparatus, the type in which four developing devices or process cartridges are disposed in series is known. However, taking into consideration that reduction in machine size is a factor that increases the convenience of the user, normally the developing devices or process cartridges are disposed as close to each other as possible, and the gaps with other units are made narrow.
However, in the case of a unit that integrally includes a developing device which houses toner and a photosensitive member, the size and weight cannot be ignored. Therefore, for size reduction of the apparatus, the developing devices or process cartridges must be disposed as close to each other as possible. As a result if the location in which each unit is inserted is narrow, and if during the operation a unit is mistakenly dropped and impacts another unit, damage can be caused.
Therefore, it is possible to deal with this situation by providing a grip or the like on the units to improve the operability of removing and inserting the units. However, the unit is made larger by the grip, so the size of the body of the image forming apparatus itself that houses the units is made larger. Also, taking the layout of the image forming apparatus into consideration, there is concern that the grip will interfere with the light path of the laser which is located nearby, so there are cases where a grip cannot be simply provided.
In this way, size reduction of the image forming apparatus and operability of inserting and removing the developing device or process cartridge are in an opposing relationship, and it was very difficult to achieve the two at the same time.